A method and system for automatic gain control of frequency modulated signal reception

Abstract

The application discloses a kind of automatic gain control method and system of frequency modulation signal reception, the method includes the following steps: sampling to any two-way frequency modulation input signal, obtain two-way sampled discrete sequence;To each signal, the discrete sequence after sampling is transformed into four-way baseband signal, then according to four-way baseband signal, the signal energy of corresponding frequency modulation input signal is calculated;The signal energy of two-way signal is compared with preset energy threshold, and according to the comparison result, attenuator is opened or closed.The technical scheme of the application is relatively simple, does not need AGC equipment, reduces hardware cost;The application can be realized using general device, and the dependency of device is small, does not affect the energy comparison of two-way signal, and the attenuation control generated is accurate and reliable.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology, and in particular to an automatic gain control method and system for frequency modulation signal reception. Background Technology

[0002] Traditional automatic gain control (AGC) methods for FM signal reception involve adding an AGC device to the RF front-end to maintain the signal within a certain amplitude range when it reaches the AD chip. However, in actual signal transmission, there are usually two or more channels. Traditional AGC methods for FM signal reception are inaccurate when comparing the energy of two or more received signals.

[0003] Furthermore, traditional automatic gain control methods for FM signal reception require additional AGC equipment, which is costly, complex in design, and highly dependent on components, increasing the risk of errors in the entire system. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] The purpose of this invention is to propose an automatic gain control method and system for frequency modulation signal reception, so as to solve the technical problems of traditional methods being highly dependent on devices and having difficulty in receiving signal energy from two or more channels.

[0006] (II) Technical Solution

[0007] To address the aforementioned technical problems, this invention proposes an automatic gain control method for frequency modulation signal reception, comprising the following steps:

[0008] Sampling of any two frequency-modulated input signals yields a discrete sequence after sampling.

[0009] For each signal, the sampled discrete sequence is transformed into four baseband signals, and then the signal energy of the corresponding frequency-modulated input signal is calculated based on the four baseband signals.

[0010] The signal energy of the two signals is compared with a preset energy threshold, and the attenuator is turned on or off based on the comparison result.

[0011] Furthermore, sampling any two FM input signals includes the following steps:

[0012] Sampling frequency is Sampling interval The sampled discrete sequence for: ;

[0013] in, The analog signal before sampling For time, The number of sampling points. It is a unit sample signal.

[0014] Furthermore, the sampled discrete sequence is transformed into four baseband signals, including the following steps:

[0015] The high-frequency portion of the sampled discrete sequence is mixed with I-path and Q-path and low-pass filtered respectively to obtain the I-path and Q-path of the high-frequency portion of the discrete sequence.

[0016] The low-frequency portion of the sampled discrete sequence is mixed with I-path and low-pass filtered with Q-path respectively to obtain the I-path and Q-path of the low-frequency portion of the discrete sequence.

[0017] Furthermore, the four baseband signals include:

[0018] ;

[0019] in, For the low-frequency portion of the discrete sequence, the I-path is used. The Q-path is the low-frequency portion of the discrete sequence; For the high-frequency portion of the discrete sequence, the I-path; The Q-path is the high-frequency portion of the discrete sequence; This indicates a low-pass filter.

[0020] Furthermore, the signal energy of the corresponding frequency-modulated input signal is calculated based on the four baseband signals, including the following steps:

[0021] Determine the amplitude energy of a single sampling point based on the four baseband signals. ;

[0022] The amplitude energy of each sampling point The sum of these values ​​serves as the signal energy of the frequency modulation input signal.

[0023] Furthermore, the amplitude energy of a single sampling point is: ;

[0024] The signal energy is: ;in, It is the maximum number of sampling points.

[0025] Furthermore, The value can be 256, 1024, 2048 or 4096.

[0026] Furthermore, the preset energy threshold includes: a first predetermined value and a second predetermined value;

[0027] The signal energy of the two signals is compared with a preset energy threshold, and the attenuator is controlled to turn on or off based on the comparison result, including the following steps:

[0028] If the energy of both signals exceeds the first predetermined value, a high level is output to the attenuator to control the attenuator to turn on.

[0029] If the signal energy of both channels is less than the second predetermined value, a low level is output to the attenuator to control the attenuator to turn off.

[0030] Furthermore, the first predetermined value ranges from 4dB to 6dB, and the second predetermined value ranges from -36dB to -34dB.

[0031] This invention also proposes an automatic gain control system for frequency modulation signal reception, comprising:

[0032] The AD sampling module is used to sample any two frequency-modulated input signals to obtain a discrete sequence after sampling.

[0033] The energy calculation module is used to transform the sampled discrete sequence of each signal into four baseband signals, and then calculate the signal energy of the corresponding frequency-modulated input signal based on the four baseband signals.

[0034] The gain control module is used to compare the signal energy of the two signals with a preset energy threshold, and control the attenuator to open or close based on the comparison result.

[0035] (III) Beneficial Effects

[0036] The automatic gain control method and system for frequency modulation signal reception proposed in this invention are relatively simple to implement, do not require AGC equipment, and reduce hardware costs; this invention can be implemented using general-purpose components, has low dependence on components, does not affect the energy comparison of the two signals, and attenuation control is accurate and reliable. Attached Figure Description

[0037] Figure 1 This is a flowchart of an automatic gain control method for frequency modulation signal reception according to an embodiment of the present invention.

[0038] Figure 2 This is a block diagram of an automatic gain control system for frequency modulation signal reception according to an embodiment of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the specific embodiments described herein are merely for further explanation of the invention and do not limit the scope of protection of the invention. The invention includes, but is not limited to, the following embodiments. Furthermore, it should be noted that, for ease of description, only the parts closely related to the embodiments are shown in the drawings; complete embodiments may also include parts not shown in the figures. In the figures, the same reference numerals denote the same or similar parts.

[0040] Furthermore, the described features, structures, or characteristics can be combined in one or more embodiments in any suitable manner. Numerous specific details are provided in the following description to give a full understanding of the embodiments. However, those skilled in the art will recognize that the technical solutions of the invention can be practiced without one or more of the specific details, or other alternatives may be employed. It is understood that the block diagrams shown in the accompanying drawings do not necessarily correspond to physically independent entities.

[0041] like Figure 1 As shown, an embodiment of the present invention provides an automatic gain control method for frequency modulation signal reception, the method comprising the following steps:

[0042] Step S1: Sample any two frequency-modulated input signals to obtain the discrete sequences after sampling.

[0043] Step S2: For each signal, the sampled discrete sequence is transformed into four baseband signals, and the signal energy of the corresponding frequency modulation input signal is calculated based on the four baseband signals.

[0044] Step S3: Compare the signal energy of the two signals with the preset energy threshold, and control the attenuator to open or close according to the comparison result.

[0045] The technical solution of this invention is relatively simple to implement, does not require AGC equipment, and reduces hardware costs; this invention can be implemented using general-purpose components, has little dependence on components, does not affect the energy comparison of the two signals, and attenuation control is accurate and reliable.

[0046] The following section provides a detailed explanation of the specific execution steps.

[0047] As a specific embodiment, the specific steps of the automatic gain control method for frequency modulation signal reception according to the present invention are as follows:

[0048] Step 1: Build an automatic gain control system

[0049] The automatic gain control system includes: an AD sampling module, an energy calculation module, and a gain control module;

[0050] The function of the AD sampling module is to sample any two FM input signals.

[0051] The function of the energy calculation module is to perform I-channel and Q-channel mixing and low-pass filtering on the low-end and high-end frequency portions of the two signals respectively, transform them into four baseband signals, and determine the energy of each of the two channels with 2048 sampling points.

[0052] The function of the gain control module is to determine whether the signal energy value exceeds a first predetermined value or is less than a second predetermined value. The range of the first predetermined value is 4dB to 6dB, preferably 5dB; the range of the second predetermined value is -36dB to -34dB, preferably -35dB.

[0053] Step 2: The AD sampling module samples any two FM input signals.

[0054] Sampling is performed on any two FM input signals, and the sampling method for the two FM input signals is the same.

[0055] The sampling frequency of one of the frequency modulation input signals is Sampling interval The sampled discrete sequence for:

[0056]

[0057] This is the analog signal before sampling. For time. This represents the number of sampling points. It is a unit sample signal.

[0058] Step 3: The energy calculation module calculates the energy of the sampled signal.

[0059] The high-frequency portion of the sampled discrete sequence is subjected to I-path and Q-path mixing and low-pass filtering, respectively. The high-frequency portion is the high-frequency part of the FM signal.

[0060] The low-frequency portion of the sampled discrete sequence is subjected to I-path and Q-path mixing and low-pass filtering, respectively. The low-frequency portion is the lower frequency part of the FM signal.

[0061] Ultimately, it is converted into four baseband signals:

[0062] ;

[0063] This refers to the I-path of the low-frequency portion of the discrete sequence.

[0064] This is the Q-path for the low-frequency portion of the discrete sequence.

[0065] This refers to the I-path of the high-frequency portion of the discrete sequence.

[0066] The Q-path is the high-frequency portion of the discrete sequence.

[0067] This indicates a low-pass filter.

[0068] The amplitude energy of a single sampling point is determined by the following formula. and the energy of multiple sampling points :

[0069] ;

[0070] ;

[0071] It is the maximum number of sampling points. The values ​​are 256, 1024, 2048, or 4096, with 2048 being the best.

[0072] Thus, the results of any two FM input signals are obtained. and .

[0073] Step 4: The gain control module is used to determine whether the signal energy value exceeds the first predetermined value or is less than the second predetermined value.

[0074] If the energy of both signals exceeds the first predetermined value, a high level is output to the attenuator to control the attenuator to turn on.

[0075] If the signal energy of both channels is less than the second predetermined value, a low level is output to the attenuator to control the attenuator to turn off.

[0076] The first predetermined value ranges from 4dB to 6dB, preferably 5dB, and the second predetermined value ranges from -36dB to -34dB, preferably -35dB.

[0077] This completes the automatic gain control for FM signal reception.

[0078] like Figure 2 As shown, an embodiment of the present invention also provides an automatic gain control system for frequency modulation signal reception, including: a sampling module 201, an energy calculation module 202, and a gain control module 203.

[0079] AD sampling module 201 is used to sample any two frequency-modulated input signals to obtain a discrete sequence after sampling.

[0080] The energy calculation module 202 is used to transform the sampled discrete sequence into four baseband signals for each signal, and then calculate the signal energy of the corresponding frequency modulation input signal based on the four baseband signals.

[0081] The gain control module 203 is used to compare the signal energy of the two signals with a preset energy threshold, and control the attenuator to open or close according to the comparison result.

[0082] In one embodiment, the two frequency-modulated signals are generated by sampling by an AD chip.

[0083] In one embodiment, the low-end frequency and high-end frequency portions of the two signals are respectively mixed by I-channel and Q-channel and low-pass filtered to transform them into four baseband signals, and the energy of each of the two channels with 2048 sampling points is calculated.

[0084] In one embodiment, it is determined whether the signal energy value exceeds a first predetermined value or is less than a second predetermined value. The range of the first predetermined value is 4dB to 6dB, preferably 5dB, and the range of the second predetermined value is -36dB to -34dB, preferably -35dB.

[0085] The overall technical solution provided by this invention can maintain the signal amplitude within the range that the AD chip can recognize by controlling the switch of the attenuator, and the result is accurate and reliable. As for the specific implementation, replacement and adjustment of each step, traditional implementation methods can be adopted, but the technical effect of the overall technical solution of this invention will not be affected.

[0086] The specific functions and roles of each module of the system in this embodiment have been described in detail in the embodiments of the relevant methods, and will not be repeated in this embodiment.

[0087] The above-described embodiments are merely typical implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of protection of this invention. The scope of protection of this invention should be determined by the appended claims. Those skilled in the art, after reading the specification and practicing the embodiments given herein, will readily conceive of other embodiments of the present invention. For those skilled in the art, several non-essential improvements and adjustments can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. An automatic gain control method for frequency modulation signal reception, characterized in that, The steps include the following: S1, sample any two frequency-modulated input signals to obtain two discrete sequences after sampling, wherein the discrete sequence after sampling of each signal... for: In the formula, Indicates the sampling interval. Indicates the sampling frequency. The analog signal before sampling For time, The number of sampling points. It is a unit sample signal; S2, for each signal, the sampled discrete sequence is transformed into four baseband signals, and then the signal energy of the corresponding frequency modulation input signal is calculated based on the four baseband signals; The step of transforming the sampled discrete sequence into four baseband signals includes the following steps: performing I-channel and Q-channel mixing and low-pass filtering on the high-frequency portion of the sampled discrete sequence to obtain the I-channel high-frequency portion of the discrete sequence. and Q Road The low-frequency portion of the sampled discrete sequence is mixed and low-pass filtered using both I-path and Q-path methods to obtain the I-path of the low-frequency portion of the discrete sequence. and Q Road ; The The above The above The above The calculation formula is: In the formula, Indicates low-pass filtering; The step of calculating the signal energy of the corresponding frequency-modulated input signal based on the four baseband signals includes the following steps: determining the amplitude ratio energy of a single sampling point based on the four baseband signals. The amplitude energy of a single sampling point for: ; the amplitude energy of each sampling point The sum of these values ​​is used as the signal energy of the frequency-modulated input signal, where the signal energy is: In the formula, This is the maximum number of sampling points; S3 compares the signal energy of the two signals with a preset energy threshold, and controls the attenuator to open or close based on the comparison result.

2. The method according to claim 1, characterized in that: The value can be 256, 1024, 2048 or 4096.

3. The method according to claim 1, characterized in that, The preset energy thresholds include: a first predetermined value and a second predetermined value; The signal energy of the two signals is compared with a preset energy threshold, and the attenuator is controlled to turn on or off based on the comparison result, including the following steps: If the energy of both signals exceeds the first predetermined value, a high level is output to the attenuator to control the attenuator to turn on. If the signal energy of both channels is less than the second predetermined value, a low level is output to the attenuator to control the attenuator to turn off.

4. The method according to claim 3, characterized in that: The first predetermined value ranges from 4dB to 6dB, and the second predetermined value ranges from -36dB to -34dB.

5. An automatic gain control system for frequency modulation signal reception, characterized in that, include: The AD sampling module is used to sample any two FM input signals to obtain two discrete sequences after sampling. The discrete sequence after sampling for each signal is... for: In the formula, Indicates the sampling interval. Indicates the sampling frequency. The analog signal before sampling For time, The number of sampling points. It is a unit sample signal; The energy calculation module is used to transform the sampled discrete sequence of each signal into four baseband signals, and then calculate the signal energy of the corresponding frequency-modulated input signal based on the four baseband signals. The step of transforming the sampled discrete sequence into four baseband signals includes the following steps: performing I-channel and Q-channel mixing and low-pass filtering on the high-frequency portion of the sampled discrete sequence to obtain the I-channel high-frequency portion of the discrete sequence. and Q Road The low-frequency portion of the sampled discrete sequence is mixed and low-pass filtered using both I-path and Q-path methods to obtain the I-path of the low-frequency portion of the discrete sequence. and Q Road ; The The above The above The above The calculation formula is: In the formula, Indicates low-pass filtering; The step of calculating the signal energy of the corresponding frequency-modulated input signal based on the four baseband signals includes the following steps: determining the amplitude ratio energy of a single sampling point based on the four baseband signals. The amplitude energy of a single sampling point for: ; the amplitude energy of each sampling point The sum of these values ​​is used as the signal energy of the frequency-modulated input signal, where the signal energy is: In the formula, This is the maximum number of sampling points; The gain control module is used to compare the signal energy of the two signals with a preset energy threshold, and control the attenuator to open or close based on the comparison result.

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